AbstractComputed dynamic waveforms were compared with measured ones for the power supply of the Compact Helical System (CHS) of the National Institute for Fusion Science during 1.5 Tesla operation and were found to be in good agreement.On the basis of these results, designs of the upgraded power supply for 2 Tesla operation are proceeded in two cases: with and without power consumption for additional heating. In the former case, the additional heating power is supplied from the ac generator that powers the CHS coils. Electric voltages and currents in the electric circuit are shown for both cases.These designs indicate the possibility of 2 Tesla operation of CHS by addition of some components without major modification of existing components.